First Results from SMAUG: Insights into Star Formation Conditions from Spatially Resolved ISM Properties in TNG50
First Results from SMAUG: Insights into Star Formation Conditions from Spatially Resolved ISM Properties in TNG50
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DOI：
10.3847/1538-4357/ac3d2d
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发表时间：
2020-06
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通讯作者：
B. Motwani;S. Genel;G. Bryan;Chang-Goo Kim;V. Pandya;R. Somerville;Matthew C. Smith;E. Ostriker;D. Nelson;A. Pillepich;John C. Forbes;F. Belfiore;R. Pakmor;L. Hernquist
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作者：
B. Motwani;S. Genel;G. Bryan;Chang-Goo Kim;V. Pandya;R. Somerville;Matthew C. Smith;E. Ostriker;D. Nelson;A. Pillepich;John C. Forbes;F. Belfiore;R. Pakmor;L. Hernquist
星际介质在银河系以下(∼千帕秒)尺度上的物理和化学性质在控制气体形成恒星的能力方面起着不可或缺的作用。在这篇文章中，我们使用TNG50宇宙学模拟来探索恒星形成区中八个可分辨的ISM性质的物理参数空间，以限制这个超空间中存在大多数恒星形成环境的区域。我们将我们模拟的大范围质量(M⋆=107-1011M⊙)和红移(0≤z≤3)的星系解构成千帕秒大小的区域，并根据恒星形成活动和环境(径向银心位置)统计分析每个区域代表的气体/恒星表面密度、气体金属丰度、垂直恒星速度弥散、自转频率和暗物质体积密度。通过检验这些性质的恒星形成率(SFR)加权分布，我们发现恒星主要在两种不同的环境下形成，这是由星系中潜在的双组分径向SFR剖面所带来的。我们研究了这些星系的相对日冕如何依赖于星系质量和宇宙时间。我们还将我们的发现与积分场光谱观测的结果进行了比较，找到了相似之处和不同之处。此外，利用降维方法，我们对上述超空间进行了表征，以揭示ISM属性之间高度的多重共线性关系，这些关系推动了恒星形成在千帕秒尺度上的分布。在此基础上，我们证明了基于多变量半径关系的简化3D表示足以捕捉原始8D空间中的大部分方差。
Physical and chemical properties of the interstellar medium (ISM) at subgalactic (∼kiloparsec) scales play an indispensable role in controlling the ability of gas to form stars. In this paper, we use the TNG50 cosmological simulation to explore the physical parameter space of eight resolved ISM properties in star-forming regions to constrain the areas of this hyperspace where most star-forming environments exist. We deconstruct our simulated galaxies spanning a wide range of mass (M ⋆ = 107–1011 M ⊙) and redshift (0 ≤ z ≤ 3) into kiloparsec-sized regions and statistically analyze the gas/stellar surface densities, gas metallicity, vertical stellar velocity dispersion, epicyclic frequency, and dark-matter volumetric density representative of each region in the context of their star formation activity and environment (radial galactocentric location). By examining the star formation rate (SFR) weighted distributions of these properties, we show that stars primarily form in two distinct environmental regimes, which are brought about by an underlying bicomponent radial SFR profile in galaxies. We examine how the relative prominence of these regimes depends on galaxy mass and cosmic time. We also compare our findings with those from integral field spectroscopy observations and find similarities as well as departures. Further, using dimensionality reduction, we characterize the aforementioned hyperspace to reveal a high degree of multicollinearity in relationships among ISM properties that drive the distribution of star formation at kiloparsec scales. Based on this, we show that a reduced 3D representation underpinned by a multivariate radius relationship is sufficient to capture most of the variance in the original 8D space.